Micromechanical behavior of jointed rock masses under uniaxial compression loading: a numerical study based on the discrete element method

The discrete element method is used to study the deformation process and failure mechanism of rock masses under uniaxial compression when the initial joint frequency increases. In this study, a systematic analysis is carried out to investigate failure mechanisms in rock masses with special emphasis on macroscopic deformation processes and the micromechanical origin. The influences of joints on strength, deformability, stress–strain relationship, and failure mode are studied at the macroscopic level. The tensile and shear crack distribution, fragment characteristics, and energy dissipation are also analyzed to advance the understanding of the deformation process and failure mechanism of jointed rock masses. The microevolution of fabric and forces anisotropy during loading and contact force distribution provide insights into the effect of increasing initial joint frequency on the macroscopic deformation behavior of rocks. The results reveal that with the increasing initial joint frequency, the specimen exhibits brittle-ductile characteristics, and the failure mode changes from splitting to sliding along the joint surfaces. They also show how the deceleration in the growth of fabric and contact forces anisotropy develops and confirm that the increase in initial joints and corresponding microstructural changes can suppress the development of anisotropy, thereby significantly reducing the strength of rock samples.